Preventing internal wear of production pipe strings by abrasive-laden fluids



PREVENTING iNTERNAL WEAR 0F PRODUCTION PIPE STRINGS BY ABRASIVE-LADENFLUIDS Filed 001;. 24, 1960 F|G.I. FIG.2.

Dec. 25, 1962 J L. RIKEETAL 3,070,171

INVENTORS. JAMES L. RIKE, WILLIAM c. LINDSEY,

ATTORNEY.

United States Patent Ofiice 3,070,171 Patented Dec. 25, 1962 3,070,171PREVENTING INTERNAL WEAR F PRODUC- TiON PIlE STRINGS BY ABRASIVE-LADENFLUIDS James L. Rike and William C. Lindsey, Houston, Tex., assignors,by mesne assignments, to Jersey Production Research Company, Tulsa,Okla., a corporation of Delaware Filed Oct. 24, 1960, Ser. No. 64,649 7Claims. (Cl. 166-243) This invention relates to the production ofhydrocarbons from wells in the earth, and more particularly to theprevention of erosion of the interior of production pipe strings byabrasive-laden fluids from subsurface earth formations.

In a conventional oil well installation, a pipe string is cemented tothe sides of a borehole to serve as a borehole liner for the purpose ofpreventing the sides of the borehole from caving in. One or moreproduction pipe strings, or flow tubings, are suspended from a wellheadapparatus, the number of production pipe strings depending on the numberof earth formations to be produced through the well bore. In some areasit has been found practical to eliminate the borehole lining, or casing,and to cement production pipe strings directly to the walls of theborehole. The cementing operation is necessary to prevent fluidcommunication between productive earth formations and to preventcontamination of fresh water sands near the earths surface byhydrocarbonaceous fluids. After the production pipe strings have beencemented they are perforated to open fluid communication between theproductive earth formations and the interiors of the pipe strings.Inasmuch as it is desirable to have only one pipe string in fluidcommunication with a given earth formation, various techniques have beendeveloped for the purpose of preventing the accidental perforation oftwo pipe strings at the same level so as to open up fluid communicationbetween pipe strings.

It is well known that sand and other abrasive materials may be producedalong with earth formation fluids. Often the velocity of the formationfluids through the perforations is so great that the abrasive particlestherein erode or abrade the inner wall of the pipe string to formopenings in the pipe string and the surrounding cement. This erosion isparticularly undesirable when the longitudinal axis of a perforation isin line with an adjacent pipe string in a multiply completed well. It ismanifest that if the erosion were continued for a sufliciently longinterval of time, fluid communication could be opened up between theproduction pipe strings. Under any circumstances, the erosion is mostundesirable.

in accordance with one aspect of the present invention, there isprovided an elongated member of an erosion or abrasion-resistantmaterial which is adapted to be positioned in a production pipe stringopposite the perforations therein. For the purpose of the presentinvention, the terms erosion and abrasion will be used to designatesubstantially the same concept. The invention contemplates that the pipestrings extend into a borehole from a wellhead at the earths surface,and that the pipe string is cemented to the sides of the borehole. Theabrasion-resistant member comprises at least three wings or finsradially extending from a central axis toward the inner wall of theproduction pipe string within which it is disposed. Preferably, the finsextend to within about one-eighth inch of the inner surface of theproduction pipe string. Abrasive-laden fluids entering the pipe stringthrough the perforations will strike the elongated member, and thekinetic energy of the abrasive particles will be absorbed by theelongated member. The fluids may then flow upwardly through the spacesbetween the fins into the open bore of the pipe string.

Objects and features of the invention not apparent from the abovediscussion will become evident upon consideration of the followingdescription of the invention taken in connection with the accompanyingdrawing, wherein:

FIG. 1 is a sectional view of a well installation making use of theinvention;

IG. 2 is a view similar to FIG. 1 illustrating another embodiment of theinvention;

FIG. 3 is a cross-sectional view taken along section 33- of FIG. 1;

FIG. 4 is a cross-sectional view of the production pipe string 3 of FIG.1, similar to FIG. 3, and illustrating another embodiment of theinvention; and

FIG. 5 is a view similar to FIG. 4 illustrating still another embodimentof the invention.

With reference now to FIG. 1, there is shown a borehole 1 within whichare disposed side-by-side production pipe strings 3 and 5 which extendfrom a wellhead apparatus (not shown) at the earths surface. The pipestrings 3 and 5 have been cemented with cement 4 to bond the pipestrings to the sides of the borehole for prevention of fluid migrationthrough the space between the pipe strings and the sides of theborehole. This is in accordance with usual practice and will not befurther discussed herein.

The lowermost section 22 of pipe string 3 is connected to the uppersection of the pipe string by an elongated collar member 7 so as to forman elongated collar recess 9. The function of this collar recess will bedescribed below.

Lowermost pipe string section 22 is shown as having been perforated sothat a plurality of perforations 21 extend from the bore of the pipestring through the surrounding cement 4 into the hydrocarbon-productiveearth formation 23. A bull plug 27 is used to close the lower end of theproduction pipe string 3. Production pipe string 5 is shown as extendingat least to the level of hydrocarbon-productive earth formation 26 andas having been perforated so as to open fluid communication between theformation 26 and the bore of pipe string 5.

Elongated member 16 comprises a plurality of fins or wings of anabrasion-resistant material. The fins radially extend from a centralaxis toward the inner wall of the production pipe string section 22. Inthe embodiment illustrated in FIGS. 1 and 3, the cross section of theelongated member is is an X, or cross, with the angle between the finsbeing substantially Preferably, the fins 17, 18, 19, and 2% are at leastthree in number, and when at least three fins are used, they aresubstantially equiangularly spaced around the longitudinal axis of theabrasionresistant member 16. The fins 18 and 19 may comprise a singlemember, with the fins l7 and 2t welded together.

The material from which the abrasion-resistant member 16 is formed maybe any of a number of ceramic materials, abrasion-resistant metals, orother materials. Tungsten carbide is a material that is particularlywell suited for use with the present invention.

The length of abrasion-resistant member 16 is at least the distancebetween the uppermost and lowermost of the perforations 21. Preferably,the abrasion-resistant menr er 16 extends at least 12 inches above andbelow the uppermost and lowermost of the perforations.

The abrasion-resistant member 16 is shown in FIG. 1 as being positionedopposite the perforations 21 by means of a collar stop or landingmandrel 15 including a plurality of latching dogs 11 radiallyspring-biased from the body of the mandrel 15 so as to extend into thecollar recess 9. Latching dogs 11 have tapered upper surfaces to permitretrieval of the apparatus from the pipe string. The collar stop 15 maybe a device as illustrated on page 3990 of the 21st edition of theComposite Catalog of Oil Field and Pipe Line Equipment (1955), and maybe run into the well on a Type A Otis Collar Stop running tool. Afishing neck 13 is provided which is adapted to be caught by aconventional wire line retrieving tool for the purpose of retrieving theapparatus from the well.

After the pipe strings have been cemented and perforated in the borehole1, the abrasion-resistant member 16 is dropped into the pipe string 3 orrun in on a wire line. When the member reaches the depth of formation23, dogs 11 are latched in collar recess Formation 23 may then beproduced. Abrasive-laden fluid entering the bore of the pipe stringthrough perforations 21 will strike the abrasion-resistant member 16 andwill flow upwardly around the mandrel 15 into the open bore of pipestring 3. The kinetic energy of the abrasive particles will be absorbedby the abrasion-resistant member 16 and will not damage the interior ofthe pipe string 3.

FIG. 2 illustrates another means for positioning the abrasion-resistantmember 16 opposite perforations 21. A spacer bar 25 is affixed to thelower end of the abrasion-resistant member 16 so that the lower end ofspacer bar 25 rests on bull plug 27 or any solid bottom such as a bridgeplug, cement, sand, gravel, etc. Fishing neck 14 is directly connectedto the upper end of abrasion-resistant member 16; otherwise, theapparatus of FIG. 2 is the same as the apparatus of FIG. 1, both inoperation and in construction.

The cross-sectional configuration of abrasion-resistant member 16 may bedifferent from the cross illustrated in FIG. 3. For example, three finsmay be disposed about the central longitudinal axis to form a V as isshown in FIGS. 4 and 5. As illustrated in FIG. 4, the fins 31 and 33 maybe shorter than fin 29 so that the axis 35 is substantially removed fromthe axis of the production pipe string 3, or the fins may be of equallength as shown in FIG. 5. More than four fins may extend from thecentral longitudinal axis 35. However, the number of fins should notexceed six to prevent undue restriction of flow upwardly through thespace between the fins. In order to insure that the abrasive fluidsejected from the perfora tions 21 will strike the abrasion-resistantfins, the fins should extend to within about one-eighth inch of theinner surface of the pipe string 3.

The invention is most advantageous in that it is very easy to constructand to position in a well. The apparatus may be easily and inexpensivelyplaced in operating position and retrieved from the well in the eventthat replacement becomes desirable.

The invention is not necessarily to be restricted to the specificstructural details or arrangement of parts herein set forth, as variousmodifications thereof may be effected without departing from the spiritand scope of the invention.

The objects and features of the invention having been completelydescribed above, what it is desired to claim is:

1. Apparatus for reducing abrasion of the interior of a production pipestring cemented to the sides of the borehole, and perforated to openfluid communication to surrounding earth formations, comprising: aplurality of erosion-resistant, elongated fins radially extending from acommon axis; and means connected to said fins for positioning said finsopposite the perforations in the pipe string.

2. Apparatus for reducing abrasion of the interior of a production pipestring cemented to the sides of the borehole, and perforated to openfluid communication to surrounding earth formations, comprising: atleast three erosion-resistant, elongated fins radially extending from acommon axis toward the inner surface of the pipe string; and meansconnected to said fins for positioning said fins opposite theperforations in the pipe string.

3. Apparatus for reducing abrasion of the interior of a production pipestring cemented to the sides of the borehole, and perforated to openfluid communication to surrounding earth formations, comprising: atleast three erosion-resistant, elongated fins radially extending from acommon axis to within about one-eighth inch of the inner surface of thepipe string, and substantially equiangularly spaced around said axis;and means connected to said fins for positioning said fins opposite theperforations in the pipe string.

4. The combination of claim 1 wherein the cross-sectional configurationof the fins is substantially that of a cross.

5. The combination of claim 1 wherein the cross-section configuration ofthe fins is substantially that of a Y.

6. In combination: a production pipe string cemented to the sides of aborehole including a plurality of pipe sections connected end-to-end bycoupling collars to define a plurality of collar recesses therebetweenopening into the bore of the pipe string; a plurality of erosionresistant elongated fins radially extending from a common axis towardthe inner surface of the pipe string; and collar stop means connected tosaid fins including means extending into one of said recesses toposition said fins opposite the perforations in the pipe string.

7. In combination: a production pipe string cemented to the sides of aborehole including a plurality of pipe sections connected end-to-end bycoupling collars to define a plurality of collar recesses therebetweenopening into the bore of the pipe string; at least threeerosionresistant elongated fins radially extending from a common axis towithin about /8 inch of the inner surface of the pipe string; and collarstop means connected to said fins including means extending into one ofsaid recesses to position said fins opposite the perforations in thepipe string.

References ited in the file of this patent UNITED STATES PATENTS'1,275,108 Vissering Aug. 6, 1918 2,046,870 Clasen et al. July 7, 19362,116,408 OLeary et al. May 3, 1938 2,923,357 Daflin Feb. 2, 1960'

